Re: [syzbot] BUG: unable to handle kernel NULL pointer dereference in __d_instantiate

* Re: [syzbot] BUG: unable to handle kernel NULL pointer dereference in __d_instantiate
       [not found] <0000000000005c2d1f05e8945724@google.com>
@ 2022-09-13 20:14 ` Andreas Dilger
  2023-09-15 19:01 ` [syzbot] [ntfs3?] " syzbot
  1 sibling, 0 replies; 2+ messages in thread
From: Andreas Dilger @ 2022-09-13 20:14 UTC (permalink / raw)
  To: syzbot
  Cc: linux-fsdevel, syzkaller-bugs, Alexander Viro, ntfs3, Konstantin Komarov

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> On Sep 13, 2022, at 1:51 PM, syzbot <syzbot+29dc75ed37be943c610e@syzkaller.appspotmail.com> wrote:
> 
> Hello,
> 
> syzbot found the following issue on:

This is almost certainly an NTFS3 error handling bug due to mounting the
broken filesystem image, but the NTFS3 maintainer and list were not CC'd.

Cheers, Andreas

> 
> HEAD commit:    a6b443748715 Merge branch 'for-next/core', remote-tracking..
> git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
> console output: https://syzkaller.appspot.com/x/log.txt?x=16271d4f080000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=e79d82586727c5df
> dashboard link: https://syzkaller.appspot.com/bug?extid=29dc75ed37be943c610e
> compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
> userspace arch: arm64
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=162474a7080000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=119b6b78880000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/1436897f0dc0/disk-a6b44374.raw.xz
> vmlinux: https://storage.googleapis.com/68c4de151fbb/vmlinux-a6b44374.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+29dc75ed37be943c610e@syzkaller.appspotmail.com
> 
> ntfs3: loop0: Different NTFS' sector size (1024) and media sector size (512)
> ntfs3: loop0: RAW NTFS volume: Filesystem size 0.00 Gb > volume size 0.00 Gb. Mount in read-only
> ntfs3: loop0: Failed to load $Extend.
> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008
> Mem abort info:
>  ESR = 0x0000000096000006
>  EC = 0x25: DABT (current EL), IL = 32 bits
>  SET = 0, FnV = 0
>  EA = 0, S1PTW = 0
>  FSC = 0x06: level 2 translation fault
> Data abort info:
>  ISV = 0, ISS = 0x00000006
>  CM = 0, WnR = 0
> user pgtable: 4k pages, 48-bit VAs, pgdp=0000000109094000
> [0000000000000008] pgd=080000010aed9003, p4d=080000010aed9003, pud=080000010738d003, pmd=0000000000000000
> Internal error: Oops: 96000006 [#1] PREEMPT SMP
> Modules linked in:
> CPU: 0 PID: 3027 Comm: syz-executor119 Not tainted 6.0.0-rc4-syzkaller-17255-ga6b443748715 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
> pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : d_flags_for_inode fs/dcache.c:1980 [inline]
> pc : __d_instantiate+0x2a0/0x2e4 fs/dcache.c:1998
> lr : d_flags_for_inode fs/dcache.c:1979 [inline]
> lr : __d_instantiate+0x80/0x2e4 fs/dcache.c:1998
> sp : ffff8000126f3ac0
> x29: ffff8000126f3ac0 x28: 0000000040000000 x27: ffff0000cd3a0000
> x26: ffff80000cf0e000 x25: fffffc0000000000 x24: 000000000001f000
> x23: ffff0000cd3a0000 x22: 0000000000000008 x21: 0000000000000000
> x20: ffff0000ca50ce48 x19: ffff0000c7732750 x18: 00000000000000c0
> x17: ffff80000dd3a698 x16: ffff80000db78658 x15: ffff0000c4f13500
> x14: 00000000000000b8 x13: 00000000ffffffff x12: ffff0000c4f13500
> x11: ff808000085e2a88 x10: 0000000000000000 x9 : ffff0000c4f13500
> x8 : 0000000000000000 x7 : ffff8000085e2e0c x6 : 0000000000000000
> x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000000
> x2 : 0000000000000001 x1 : 0000000000000000 x0 : 0000000000000000
> Call trace:
> d_flags_for_inode fs/dcache.c:1980 [inline]
> __d_instantiate+0x2a0/0x2e4 fs/dcache.c:1998
> d_instantiate fs/dcache.c:2036 [inline]
> d_make_root+0x64/0xa8 fs/dcache.c:2071
> ntfs_fill_super+0x1420/0x14a4 fs/ntfs/super.c:180
> get_tree_bdev+0x1e8/0x2a0 fs/super.c:1323
> ntfs_fs_get_tree+0x28/0x38 fs/ntfs3/super.c:1358
> vfs_get_tree+0x40/0x140 fs/super.c:1530
> do_new_mount+0x1dc/0x4e4 fs/namespace.c:3040
> path_mount+0x358/0x914 fs/namespace.c:3370
> do_mount fs/namespace.c:3383 [inline]
> __do_sys_mount fs/namespace.c:3591 [inline]
> __se_sys_mount fs/namespace.c:3568 [inline]
> __arm64_sys_mount+0x2f8/0x408 fs/namespace.c:3568
> __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
> invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
> el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
> do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206
> el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:624
> el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:642
> el0t_64_sync+0x18c/0x190
> Code: 79000688 52a00417 17ffff83 f9401288 (f9400508)
> ---[ end trace 0000000000000000 ]---
> ----------------
> Code disassembly (best guess):
>   0:	79000688 	strh	w8, [x20, #2]
>   4:	52a00417 	mov	w23, #0x200000              	// #2097152
>   8:	17ffff83 	b	0xfffffffffffffe14
>   c:	f9401288 	ldr	x8, [x20, #32]
> * 10:	f9400508 	ldr	x8, [x8, #8] <-- trapping instruction
> 
> 
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
> 
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> syzbot can test patches for this issue, for details see:
> https://goo.gl/tpsmEJ#testing-patches

Cheers, Andreas

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